The authors have no funding, financial relationships, or conflicts of interest to disclose.
Transoral robotic nasopharyngectomy was carried out for a patient who developed recurrent nasopharyngeal cancer after radiotherapy. The tumor in the left lateral wall of the nasopharynx was exposed after splitting the soft palate and a curative resection, including the medial crus of the eustachian tube was carried out under the three-dimensional 0° camera. The operative procedure was uncomplicated, blood loss was minimal and the patient recovered smoothly. The camera of the surgical robot provided superb visualization of the operative field and the maneuverability of the robotic arms with the Endowrist design allowed adequate tumor extirpation. The morbidity associated with the procedure was minimal, and this surgical procedure can be applied for resection of small and favorably located residual or recurrent nasopharyngeal cancer or other appropriate pathologies in the region. Laryngoscope, 2010
The primary management of early stage nasopharyngeal carcinoma is radiotherapy and for advanced stage disease concomitant chemoradiation. In recent years, with the application of intensity modulated radiotherapy, the local tumor control rate has improved. There are, however, still a number of patients who have residual disease or develop recurrent tumor after initial therapy. The complications associated with further external radiotherapy in the management of these patients are significant. The logical alternative for the management of these residual or recurrent tumors is surgery.
Anatomically, the nasopharynx is situated in the center of the head; it is over 10 cm from the skin from all surfaces. This region is difficult to examine and to get an adequate exposure for the removal of a malignant tumor. Various approaches have been described in the literature and they all required external incisions and there were associated morbidities.1–4 Transnasal endoscopic approach has been reported for resection of small tumors in the nasopharynx.5, 6 The ordinary instruments for nasoendoscopic surgery currently available limit the oncologic resection of these tumors, especially on the lateral aspect.
The efficacy of transoral robotic surgery in otolaryngology–head and neck surgery has been well documented. In most clinical reports this was employed for the management of pathologies in the oropharynx,7, 8 supraglottic larynx,9 and upper hypopharynx.10 In cadavers, its application on the skull base11 and the nasopharynx12 has also been reported. We have carried out transoral robotic resection of recurrent nasopharyngeal carcinoma after radiotherapy for a patient and wish to report the technique and result.
Patient and Surgical Technique
A female patient, 78 years old, suffered from carcinoma of the nasopharynx and was treated 7 years ago with a radical dose of radiation. On follow-up, a recurrent tumor was detected in the left fossa of Rosenmüller (Fig. 1). Biopsy of the tumor confirmed it to be recurrent carcinoma, and there was no metastasis in the neck or the rest of the body. Magnetic resonance imaging showed that the tumor was localized in the posterolateral part of the nasopharynx, not adherent to the internal carotid artery (Fig. 1). The patient consented to transoral robotic resection of the recurrent nasopharyngeal carcinoma.
The surgery was carried out at Queen Mary Hospital, The University of Hong Kong, Hong Kong under general anesthesia. The patient was placed in a supine position and a nonkinking endotracheal tube was inserted and placed over the central lower lip. A Dingman mouth gag with the longest blade was inserted. An incision was started from the left base of the uvula and extended along the midline of the soft palate onto the mucoperiosteum over the hard palate for half the length of the hard palate. With diathermy the attachment of the soft palate was detached from its insertion on the hard palate from midline to the lateral pharyngeal wall. Stay sutures were placed along the incised edge of the soft palate and the mucoperiosteum of the hard palate. The suture ends were inserted into the coils of the spring over the frame of the Dingman retractor to maintain the tension for retraction (Fig. 2). The Unitrac (Aesculap, Braun, Center Valley, PA), an air pressure controlled malleable retractor holder mounted on the operating table was fixed to the handle of the Dingman retractor. This handle was lifted upward to keep the head in an extended position. Throughout the operation, the retractor holder maintained the position of the Dingman retractor in a relatively rigid form. With retraction of the soft tissue, the nasopharynx with the tumor was exposed.
The Da Vinci surgical robot, model S (Intuitive Surgical Inc., Sunnyvale, CA) was docked from the head end of the table and the 0° 8-mm dual-channel camera was introduced transorally. This allowed good visualization of the tumor in the left fossa of Rosenmüller and its surrounding tissue (Fig. 3). The 5-mm Maryland grasping forceps was mounted to the left robotic arm, and the 8-mm scissors with monopolar diathermy was mounted to the right robotic arm. The incision around the tumor was planned at 1.5 cm from the edge of the tumor, and this was marked with diathermy using the tip of the scissors. The medial crus of the left eustachian tube cushion was included in the resection (Fig. 4). The dissection started from the inferior aspect of the nasopharynx. The incision went through mucosa and the prevertebral muscle. The tumor and its surrounding tissue was then lifted with the Maryland forceps and the scissors with diathermy cut and cauterized the deep aspect of the nasopharyngeal tissue. On the lateral aspect, the lateral crus was retracted laterally with the Maryland forceps and the diathermy cut through the opening of the eustachian tube between the two cartilaginous crura. The medial crus was included in the specimen. Superiorly, the diathermy incised through the nasopharyngeal mucosa down to bone. The scissors in the right robotic arm were then replaced by the 8-mm diameter hook with diathermy, which was used to lift the soft tissue off the bone, and all tissue above the bone was included in the resection. The tumor with a margin of soft tissue was removed en bloc (Fig. 5). The internal carotid artery was not seen during dissection. Frozen section of all margins were free of tumor. Following resection of the tumor, the defect in the nasopharynx was a slanting trough. The deepest part in the center was bone followed by different layers of prevertebral muscle, submucosa on the side, and then normal mucosa of the nasopharynx. A free mucosal graft was taken from the posterior oropharyngeal wall to be placed over the raw area in the nasopharynx. A nasogastric tube was inserted through the right nasal cavity. The nasopharynx and the left nasal cavity were packed with Merocel. The palatal wound was closed with absorbable sutures in three layers.
Employing this split palate approach together with the use of the robot, adequate visualization of the nasopharynx could be achieved during the entire resection process. With the versatile Endowrist of the robotic arm, dissection around the tumor in all directions could be done under direct vision with ease, and en bloc tumor resection with adequate margins was possible. Hemostasis was adequate with the diathermy. The whole operation lasted 2 hours and 30 minutes, and blood loss was minimal.
The patient recovered from the operation smoothly. Nasal packing was removed on the 2nd day, and she was able to take oral food on the 4th postoperative day.
Robotic surgical procedures are currently used in the disciplines of urology and gynecology. It has gained increasing application in otolaryngology, head and neck surgery, and especially for pathologies in the oropharyngeal region.13 The functional outcome was reported to be superior to other treatment options.14 This might be due to the combination of improved visualization, less traumatic tissue handling, and the ability to perform dissection around corners. It has also been reported in cadavers for dissection of the upper cervical vertebra.15
Recurrent nasopharyngeal cancer after radiation usually has extensive tissue involvement. Adequate exposure of the region is essential for an oncologic resection. We have employed the maxillary wing approach for salvage surgery of recurrent nasopharyngeal carcinoma for the past 20 years, and the overall results have been satisfactory. When the residual or recurrent tumor is small, resection under endoscopic guidance is applicable rather than major open approach resection.
The size and the location of the tumor in the nasopharynx determine the optimal approach for the particular patient. For extirpation of those large recurrent tumors that have extended laterally, the maxillary swing approach nasopharyngectomy should be employed. For small tumors located in the middle part of posterior wall, endoscopic approach resection is appropriate. When endoscopes with sinus surgery instruments were used to assist resection of lesions located over the lateral wall affecting the fossa of Rosenmüller but not extending into the paranasopharyngeal space, it would be difficult to remove the tumor adequately, especially over the lateral aspect. The lack of appropriate curved instrument and inferior visualization contribute to the difficulty.
The transoral robotic surgical resection is applicable as shown in this patient who has a small tumor located over the lateral wall of the nasopharynx. With the split palate approach, the entire nasopharynx could be exposed, and it also allowed the insertion of the camera and the two robotic arms for removal of the recurrent tumor. The pressure-controlled retractor holder attached to the handle of the Dingman retractor kept it immobilized and maintained the head in a slightly extended position throughout the operation.
The three-dimensional camera of the surgical robot provided excellent visualization. The two robotic arms complemented each another, one for retraction and one for dissection. The maneuverability of the robotic instruments with the Endowrist design applied close to the tumor was a major advantage over ordinary nasoendoscopic instruments. For this patient, minimal assistance was provided at the operating table such as suction and minor retraction. The tumor was small, and thus adequate resection margins could be achieved with removal of the medial crus of the eustachian tube cartilage. At the completion of the robotic surgical resection, a small area of bone at the skull base was exposed. To avoid the development of osteoradionecrosis in this postradiation field, a free mucosal graft was taken to cover the raw area.
This patient recovered from the operation smoothly with minimal morbidity. Transoral robotic surgical salvage procedure for recurrent nasopharyngeal carcinoma is safe and should be employed for selected patients who have a small tumor situated over the lateral wall.